Recent content by macheung

Yes, I am planning to use something like a Bluetti AC300 for AC200Max for this, a portable unit that I can just plug in, not permanently bolted into the building. So if grid is out, I would turn off the SE main inverter (so it doesn't auto restart when grid is back up), plug the secondary PV...

I actually have a pretty unusual setup. I have 45 panels connected in 3 strings through SolarEdge optimizers to a SolarEdge grid tie inverter. The grid tie inverter shuts down when grid is lost and the optimizers shuts off at the panel. This is normal and all good. Rapid shutdown, no issues...

Note that I am not shorting an entire 600V string to ground. I am looking at a few individual panels wired separately with Isc 10A and Voc 42V.

Given that, if I only have panels that are not connected in series with Voc around 42V, can I satisfy the rapid shutdown requirement by having a shutdown switch that effectively shorts each of the panels out? Note the switch will be installed quite always from the panel, but once it is engaged...

How come? The Isc is only 10% higher than Imp, if the panel can operate indefinitely at say 9A what would make it catch fire at 10A?

Does the regulation say it must be under 30V? In the US it is 80V which is somewhat more reasonable.

Wow, 30V is a pretty low voltage requirement. Pretty much it would prevent even a single normal sized roof panel (Voc 40-45V) without a disconnect switch located right there from working. Harsh... As per the wording of the document, would it be possible to have a device that literally shorts...

I don’t have a Bluetti unit, but 20w with no output on seems like a lot. What is that thing doing? My laptop consumes 20w when it is on and doing light duty work. I have a Jackery 1500 unit and there is no on/off switch, I can turn AC/DC on but the units otherwise is off (or on). I have it...

Is that 15w burn with DC and AC output on or off? If it is with DC and especially AC on (even with no load), it is actually pretty good. I have heard stories of 30-40w consumption when DC and AC are on with no load.

I am considering a different approach to get power off a grid tied PV system when the grid is out. Instead of fooling the grid tie inverter with a local grid, I am trying to hook up another off-grid inverter to the some of the panels in parallel. For this to work, the parallel connection point...

What is the method of operation behind this?

I am aware of that, hence it is in the "Danger Zone" forum. To discuss concepts that may not be compliant with the rules as they are today. I don't want to debate NEC2017+ rapid shut down rule set, while it was ostensibly for fire fighter safety, it was heavily pushed by SolarEdge at that time...

Most of us in North America have setup that conforms to rapid shut down requirement, where the grid tie inverter would communicate with shut down devices or optimizers and shut off the power pretty much right at the panel. This prevents our solar setup to provide backup power when the grid is...

Are there grid tie inverters with a no export mode where it won’t try to push back into the grid? In that case, would a small sine wave inverter allow it to turn in safety and power local loads when the grid is off and disconnected?

How close does a nuclear detonation has to be before EMP becomes an issue? At the at distance, would the thermal or pressure wave cause concern?